Field of the Invention
The present invention relates to a light controlling apparatus, and more particularly to a light controlling apparatus that may realize a transparent mode and a light-shielding mode, a method of fabricating the light controlling apparatus, and a transparent display device including the light controlling apparatus.
Discussion of the Related Art
Recently, with the advancement of the information age, display devices for processing and displaying a large amount of information have been promptly developed. More particularly, various display devices have been introduced and spotlighted.
Detailed examples of the display devices include liquid crystal display (LCD) devices, plasma display panel (PDP) devices, field emission display (FED) devices, electroluminescence display (ELD) devices, and organic electroluminescent display (OLED) devices. The display devices generally have excellent properties of a thin profile, light weight and low power consumption and thus their application fields have been increased continuously. In particular, in most of electron devices or mobile devices, the display device has been used as one of a user interface.
Also, studies of transparent display devices through which a user may see objects or images located at an opposite side have been actively made.
The transparent display devices may have advantages of better use of space, interior and design, and may have various application fields. The transparent display devices may solve spatial and temporal restrictions of electronic devices by realizing functions of information recognition, information processing and information display as a transparent electronic device. Such transparent display devices may be used for a smart window, which may be used as a window of a smart home or a smart car.
Of the transparent display devices, the transparent display device based on LCD may be realized by applying an edge type backlight thereto. However, the transparent display device to which LCD technologies are applied has a problem in that transparency is deteriorated by a polarizing plate used for realization of black. Also, a problem occurs in outdoor visibility of the transparent display device based on LCD.
The transparent display device based on OLED has power consumption higher than that of the LCD and has a difficulty in displaying a true black. Also, although the transparent display device based on OLED has no problem in a contrast ratio under a dark environment, a problem occurs in that a contrast ratio is deteriorated under a normal environment.
Therefore, to realize a transparent mode and a light shielding mode, an apparatus based on a polymer dispersed liquid crystal (PDLC) comprised of a single layer has been suggested as a light controlling apparatus of a transparent display device based on OLED. The polymer dispersed liquid crystal (PDLC) comprised of a single layer may be formed by mixing a monomer with liquid crystals, changing the monomer to a polymer through UV hardening and making the liquid crystals at a droplet state in the polymer.
If an electric field is applied to the polymer dispersed liquid crystal (PDLC), arrangement of liquid crystals arranged in the polymer is varied. Therefore, the polymer dispersed liquid crystal (PDLC) layer may scatter or transmit light which is externally incident. That is, since an apparatus based on the polymer dispersed liquid crystal (PDLC) layer may scatter or transmit light even without a polarizing plate, the apparatus may be applied to the light controlling apparatus of the transparent display device.